ROUND ROCK, Texas — Dell says a preliminary tally shows that shareholders have approved a $24.8 billion offer from its founder to buy the company and take it private.

The deal will end the struggling computer maker’s quarter-century history as a publicly held company.

Like other PC makers, Dell Inc. has been hit hard in recent years as consumers shift their buying habits away from traditional desktops and laptops and toward tablets and other mobile devices.

Last month, Dell reported a 72 percent drop in profit for its most recent quarter, as the Round Rock, Texas, company cut prices to shore up computer sales. Dell’s stock has plunged by more than 40 percent since Michael Dell returned for a second stint as CEO in 2007.

Michael Dell, who is making the offer with a group of investors and lenders, has said he can turn the company around, but the process will involve a painful realignment that is likely to trim its earnings for another year or two. Dell has said the turnaround will be easier to pull off away from Wall Street and its fixation with short-term results.

But the offer had naysayers, who said it undervalued the company. The vote was delayed three times as a result of the opposition.